[Piglit] glx-multithread-shader-compile hung

[Jose Fonseca]

FYI, I twice now got deadlock on glx-multithread-shader-compile on my continuous testing of Mesa:

  ...
  [Sat Jul 20 01:18:20 2013] ::  running :: glx/glx-multithread-shader-compile  <-- last piglit message
  Build timed out (after 120 minutes). Marking the build as failed.   <-- Jenkins message

I'm going to disable the test on my custom test list.  But I believe that if we're going to add multi-threaded tests to piglit, then we should have a per-test timeout (ie, after a threshold time like 5min the framework should kill the process and mark the test as failed).  Otherwise these race condition tests do more harm than good -- as they prevent all other tests from running.

Jose